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Thank you for stopping by the Weather Watch 12 blog! With the ‘unofficial’ start of summer arriving this weekend, I thought it would be a great time to discuss the Weather Watch 12 long range summer forecast!
In today’s blog I will go over, what our forecast is based on, how our forecast compares to that of the Climate Prediction Center, and also give the temperature and precipitation forecast for the next 3 months!
Since starting at WISN back on December 1, I have been providing long range forecasts based on a weather pattern theory that I learned about while working in Kansas City. The theory is called the ‘LRC’, or Lezak’s Recurring Cycle.
Here is what the theory states:
- A unique weather pattern sets up every year between October 1st and November 10th
- The weather pattern cycles, repeats, and continues through winter, spring and into summer. Identifying the cycle length helps tremendously when making long range weather predictions.
- Long term long-wave troughs and ridges become established and also repeat at regular times within the cycle. These dominant repeating features are a clue to where storm systems will reach peak strength, and where they will be their weakest.
- The LRC is a winter/spring/early summer-long pattern! There is a pattern! It isn’t just one long-wave trough, storm system, or ridge. It is a sequence of troughs and ridges that are cycling across the Northern Hemisphere.
As I have mentioned many times, this year’s cycling weather pattern is on roughly a 60-62 day cycle. Looking back from when the pattern formed in October, thru the winter months, and now into Spring, will help in making an accurate long range summer forecast.
Let’s start by looking back at the pattern and what I term the ‘signature’ storm of this year’s weather pattern. The pattern is best viewed at the 500mb level, or the middle of the atmosphere since we are looking at large scale features.
The signature storm of the pattern has occurred like clockwork around October 22-25, December 21-25, February 21-24, and April 22-25. Each time through the pattern this has been a wet period with rain or snow. Let’s look back to October, and then compare it to April.
Below is the 500mb map for October 23, 2009. Notice the large low over the Midwest, this is our ‘signature’ storm.
What’s amazing is this storm repeated in December, February, and again in April. Let’s look at the 500mb map from April 25. The ‘signature’ storm once again cruised through the Midwest.
Will this storm repeat in June for a fifth time? The quick and easy answer, yes. What amazes me is not only does this feature repeat, but the overall long term long wave ridges and troughs continue to cycle! What does this year’s pattern have in storm for the summer? Here is the Weather Watch 12 Summer Forecast!
Forecast: Above Average
Discussion: The current pattern has only produced 1 month(October) with below average temperatures from October-May. I expect the trend of above average temperatures to continue into summer. The warmest temperatures of the summer may occur around July 18-25. This pairs with other warm-ups in previous parts of the cycle, including the 86 & 88 degree temperatures from May 23-24.
As a side note, Milwaukee averages 10 days each summer with a high of 90 or warmer. I think the warmest high temperature this summer in Milwaukee will be 95 degrees.
Forecast: Around Average (11.17″)
Discussion: Predicting summer rainfall is always tricky. Thunderstorms are spotty by nature, and can produce a wide range of rainfall totals. But based on the pattern over the last 8 months, I think we will hang close to average this summer in regards to rainfall.
June looks like the wettest month of the summer. Active periods for weather to watch for come around June 7-9 and then a wetter period the last week to 10 days of the month. This is when the ‘signature’ storm should occur. Severe weather season should heat up in June, and likely will be the most active of the summer. Several disturbances will pass by in the more active parts of the pattern.
***As a side note…the pattern begins to break down in late July and into August. Out of the next 3 months, the forecast confidence for August is the lowest.***
That is our summer forecast, now let’s look at the Climate Prediction Center’s temperature forecast for June-August. The forecast from the CPC calls for an increased chance of a cooler than average summer for our area.
The Climate Prediction Center’s precipitation forecast calls for about average rainfall for our region. For our area I think it will be difficult to abruptly shift from having 7 consecutive months with above average temperatures, to a pattern that keeps us cooler than average for the summer.
I would love to hear what you think! Do you think temperatures this summer will be above, near average, or below average?
Have a great day!